This invention is concerned with a mould arrangement for use in a cyclicly operating glassware forming machine, the arrangement comprising a mould comprising a bottom plate defining a bottom portion of a cavity of the mould in which molten glass is moulded in the operation of the machine, and two side portions defining side portions of the cavity, each side portion being movable in a cycle of operation of the machine to a first position thereof in which it engages the bottom plate and the other side portion to co-operate in defining the mould cavity so that moulding can take place and to a second position thereof in which the side portions are separated to allow moulded glass to be removed from the mould cavity, the side portions also defining cooling passages passing upwardly through the side portions through which air can pass to cool the side portions.
In a glass container manufacturing machine of the so-called "individual section" type, a number of container making units or sections are arranged side by side, are fed with glass from a common source, and feed their output to a common conveyor. Each of these sections has at least one parison mould in which a parison is formed from a gob of molten glass delivered to the mould, and at least one blow mould in which parisons are blown to the shape of the container. The blow mould comprises a stationary bottom plate which defines a bottom portion of a cavity of the mould and two side portions defining side portions of the cavity. The two side portions are mounted on supporting arms which are movable to move the side portions towards one another into a first, closed, position in which the side portions engage the bottom plate and each other so that a parison is enclosed in the cavity defined by the side portions and the bottom plate. The arms are also movable to move the side portions away from one another into a second, open, position to allow moulded articles to be removed from the mould.
Since the moulds of an individual section type machine absorb heat from the glass at a rate which is faster than the heat can be dissipated to the surrounding atmosphere without additional cooling, such moulds are supplied with cooling means which cool the mould so that it remains at a substantially constant average temperature during successive operations of the machine. Because the sections of an individual section type machine need to be close together, for reasons of glass supply, only very limited space is available around the mould for the provision of cooling means. One solution to this problem is to feed cooling air through the frame of the machine section to a vertical cooling stack which is provided with nozzles which direct the air on to the outside of the mould. This solution, however has the disadvantage that the arms supporting the side portions of the mould interfere with the flow of air to the mould and also it is difficult to provide differential cooling around the mould as is desirable. Furthermore, such cooling stacks are a source of undesirable noise. In another type of cooling means, cooling air is supplied through the supporting arms of the side portions of the mould to a chamber around the mould. This type has the disadvantage that it requires expensive machining of the arms, to allow both for the movement of the arms and for the flow of the cooling air. Furthermore, as a seal has to be provided between the arm and the side portion of the mould, delays occur in changing moulds and the cost of the mould is increased. It is also difficult to provide differential cooling around the mould. Attempts have also been made to cool moulds by passing cooling air through passages in the side portions thereof. Examples can be found in U.K. Pat. No. 1337292 and U.S. Pat. No. 4,251,253 (FIGS. 10 to 12). In these arrangements, air is brought through the supporting arms to the passages through pipes. Thus, expensive machining of the arms is required and also pipe connections are involved between the arms and the mould portions thereby causing delay to mould changes and increasing the cost of the moulds. Furthermore, in these arrangements the cooling air makes sharp changes of direction in the mould so that considerable resistance to air flow is created requiring the use of high pressure air to achieve adequate air flow. The use of high pressure air is undesirable because of the expense involved. Furthermore non-uniform air flow is created distorting the cooling effect and making it difficult to predict. Thus, it becomes difficult to predict where to position the cooling passages to achieve the optimum cooling effect. If the passsages are not initially correctly positioned, the cooling effect can be adjusted by inserting plugs or insulating sleeves into the passages but this is a time-consuming trial-and-error method because the effects of the plugs and/or sleeves are again hard to predict.
It is an object of the present invention to provide a mould arrangement in which passages in the side portions of the mould can be supplied with cooling air at a substantially uniform pressure and with a uniform flow pattern.